1. Field of the Invention
The present invention relates to a method and apparatus for selectively directing work objects and, more particularly, to such a method and apparatus which are operable so as to permit randomly ordered work objects to be selected during transport along a path of travel by the application of motion to the work objects so selected with an efficiency, dependability and a substantially lower risk of damage to the work objects than has heretofore been achieved in the art.
2. Description of the Prior Art
The handling, processing, packing and shipping of fungible goods characteristically requires selection from among randomly ordered goods so as to combine goods having common characteristics of a predetermined type. For example, in the handling of fresh fruits and vegetables, sorting of the goods as to such characteristics as weight, size, color, shape, maturity and the like is inherent in the process. A multiplicity of conventional methods and apparatuses have been employed in such operations and they have been developed to the point of a relatively high degree of reliability. For example, the applicant's U.S. Pat. No. 4,549,272 is directed to an article sizing apparatus for measuring the volume, weight or shape of articles, such as fresh vegetables and the like, and thereafter loading containers with the articles so selected.
Characteristically, such sorting or selecting is achieved by transporting the work objects along a path of travel, such as a conveyor system, in randomly ordered, single file subsequent to receipt of the work objects in bulk, such as in bins after harvest. During transport along the conveyor system, the work objects are subjected to any of a wide assortment of detecting or sensing apparatuses operable to determine the predetermined characteristics of each work object. Thereafter a mechanism operably connected to the sensing system is activated to displace each work object so selected in accordance with the predetermined characteristics from the conveyor system for collection with other work objects having substantially the same predetermined characteristics. In conventional practice, all such mechanisms for displacing the work objects from the path of travel require movement of a work object engaging member substantially transversely of the conveyor system to displace the work object and, subsequently, return of the work object engaging member to a start position. Such conventional mechanisms suffer from a host of problems intrinsic to the operation. Heretofore, these problems have been considered an essential, but unfortunate, result of such sorting operations.
The specific problems incident to the sorting operation are dependant, in part, upon the specific methods and apparatuses employed in the sorting process. However, certain of the problems are largely common to all such conventional practices. Thus, for example, since the work object engaging member must always return to a start position before it can be employed to displace the next successive work object from the conveyor system, movement of the work object engaging member must be at a very high velocity. While such velocities are well within the capabilities of modern technology, the perishable nature of the work objects, such as fresh fruits and vegetables, results in the work objects frequently being damaged by the application of such force thereto. In the case of fresh fruits and vegetables, this damage includes bruising and otherwise marring the work objects to a degree frequently diminishing the value of the work objects in the marketplace. Since such damage typically does not become evident for many days, it normally is not possible to select and discard the damaged work objects before they are shipped to market. This damages the market for the goods.
Similarly, because of the application of such force at high velocity, the work objects themselves are accelerated to velocities which cause them subsequently to engage other surfaces with such force as to cause similar damage. Even at such high velocities the work object engaging members must be returned across the conveyor to a start position. Since successive work objects traveled along the conveyor system frequently may also have the same predetermined characteristics requiring that they be displaced from the conveyor system, it is typically necessary to space the work objects along the conveyor system so as to allow time and space for return of the work object engaging member to the start position sufficiently soon to be able to displace the next successive work object from the conveyor system if so selected.
The equipment necessary to achieve such spacing of the work objects is not entirely dependable. Furthermore, because of the spheroid configurations of such goods as fruits and vegetables, the work objects frequently roll toward each other during transport or the conveyor system. Thus, the operative effect of the initial spacing is defeated. The work object engaging member thus is rendered ineffectual in that it fails to displace many of the work objects sensed by the sensing mechanism. The engaging member impacts many of the work objects during return to the start position thereby damaging the work objects, knocking certain other of the work objects from the machine and allowing still others to pass from the machine without the desired selection having taken place.
A still further problem chronic to most such conventional methods and apparatuses is the wearing and break down of the mechanisms operable to achieve such high velocity movement of the work object engaging member. Not only is such trauma incident to the high velocities achieved, but the trauma of reciprocal movement at high velocity is additionally severe.
Therefore, it has long been known that it would be desirable to have a method and apparatus which are operable to achieve the precise and dependable displacement of work objects in accordance with predetermined characteristics efficiently, dependably and without the multitude of problems associated with conventional methods and apparatuses.